Method of making castings.



No. 727,103. 'PATBNTED MAY 5, 190a.

" J. c. DAVIS.

JMETHOD OF MAKING GASTINGS.

APPLIOATION FILED JAR. 10'I 1902.

H0 MODEL.

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a 0 9 5 Y A M D E T N E M m 0 7 2 7 m N APPLICATION FILED JAN. 10, 1902.

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.HO MODEL.

Patented May 5, 1903.

PATENT OFFICE.

JAMES C. DAVIS, OF ST. LOUIS, MISSOURI;

METHOD OF MAKING CASTINGS.

SPECIFICATION forming part of Letters Patent No. 727,103, dated May 5,1903. Application filed January 10, 1902. Serial No. 89,104. (No model.)

T0 at whom it may concern:

Be it known'that I, JAMES C. DAVIs,a citizen of the United States,residing in the city 'of' St. Louis, in the State of Missouri, haveinvented certain new and useful Improvements in Methods of MakingCastings, of which the,

method of making castings which shall ,be of varying degrees ofhardness, thus one made of steel which shall be of a'hardtemperable:

quality around the outside and relatively more soft, andconsequentlytough and ductile, near the center.

Otherobjectsof my invention are to produce wheels of a certainpredetermined and unvarying quality ,of metal, and especially wheels inwhich the outer rim is composed of a perfectly homogeneous quality ofmetal which shall be alike in any number of wheels.

My invention is particularlydesigned for use in the formation of steelcar-wheels, and it is in connection with this that I will now proceed todescribe it.

Referring to the accompanying drawings, it will be seen that in Figure lI have illustrated a rotatable mold provided with means for mounting thesame, within which a car- In carrying out my invention I first take amold, as the car-wheel mold 6, and'place the same upon a table 7,constructed to rotate by means of thedrivin-g mechanism 8 at a'sp'e'ed,

of, say, two hundred revolutions per minute.

while the metal is being cast. The metal is then poured into the mold,as shown in Fig. 1, from some suitable ladle, as indicated at 9, and atthe same time the mold is rotated, by means of the rotating mechanism 8,at the proper speed, and coincidently with such pouring and suchrotation there is introduced into the metal as it is being poured intothe mold somehardening element of a high specific gravity relative tothe metal being castsuch, for example, as finely-divided manganese'.thisbeing introduced by suitable means,as the small ladle 10, (Shown inFig.1.

The finely-divided manganese or other hardening element being of highspecific gravity passes down into the mold, together with the metal, andas the mold is rapidly rotating is driven by the centrifugal action tothe outside thereof, the heaviest portion of the contents of the moldnaturally gravit-ating towardthe periphery of the casting, which iswhere I desire to have the greatest degree of hardparticularly that Idesire to introduce the hardening element of the character described.

The amount of hardening element added may be gradually reduced as thecasting pro grosses until toward the end thereof there may be little ornone added. This will leave the central portion of the casting ductileand soft relative to the balance thereof, although there will be nosharp dividing-line between them. The castings having been formed areplaced in a heating-furnace, as shown in Fig. 3, wherein they are raisedto a high temperature preparatory to the hardening process, which isaccomplished by means of the chilling ring or casing, (shown in Figs. 4and 5,) the wheels being placed in such ring, which I have marked 11,within the center thereof,

as shown in Fig. 5, and water orother cooling agent introduced throughthe pipe 12 and by means of the radial openings 13 in the partition 14distributed orcaused to act upon the several portions of thetread-surface of the wheel, passing off 'through the outlet tubes ordrains .15, of which there may boas many as desired. The casting havingbeen thus suitably hardened is then. removed from the chilling-ring andready for use.

' By employing a predetermined. and fixed quality and quantity of thehardening material and attending to the speed of revolution of the moldand the rate at which the hardening material is introduced any number ofwheels may be made of a known and uniform ioo composition and structure,and the tread of the wheel will be of a quality which can be temperedand treated as ordinary tool-steel, but is much superior to ordinarycast-steel. It has all the qualities of a steel-tired wheel, while thecenter of the wheel remains ductile and workable and thoroughly tough tostand the strain.

The advantages of my invention will be still more apparent when it isconsidered that the increasing weight of cars gradually coming into useis making the requirements on the wheels more and more severe until thelimit for cast-iron wheels of the usual construction has nearlyif notquite been reached. Unless a superior wheel is found to those now in usethe carrying capacity of cars cannot be much further increased so longat least as the present style of track construction continues to befollowed.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. The herein-described method of making castings, which consists inpouring into a revolving mold a mixture of fluid metal and a hardeningelement, substantially as described.

2. The herein-described method of making castings, which consists inpouring metal into a revolving mold, and during the act of pouringadding to the molten metal as it passes into the mold, a finely-dividedhardening element, substantially as described. I

3. The described method of making castings, which consists in pouringinto a revolving mold a mixture of molten metal and a hardening element,and gradually diminishing the amount of the hardening element as themold is filled, substantially as described.

4. The method of making car-Wheels which consists in providing arevolving mold therefor, pouring metal into the same and simultaneouslyintroducing a hardening element in a finely-divided state, afterwardheating the wheel, and then suddenly cooling the outer rim of the same.

5. The method of making car-wheels which consists in pouring the moltenmetal into a revolving mold, introducing at the same time a hardeningmaterial and gradually diminishing the quantity of the latter as themold is filled and afterward heating the wheel and suddenly cooling/therim thereof, whereby the rim is hardened and the metal is left more andmore malleable toward the center of the wheel.

6. The process of making cast car-wheels by providing a revolving moldtherefor, pouring molten steel thereinto and at the same timeintroducing finely-divided manganese, diminishing the amount ofmanganese as the mold is filled, then heating the finished Wheel andsuddenly cooling the outer rim thereof whereby the wheel is tempered andthe hardness varies with the distance from the center, substantially asset forth.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

JAMES C. DAVIS.

Witnesses:

GEO. G. FLOYD, WM. E. HOBLITZELLE.

